Have you tried hooking it to an external monitor? When you disconnected the battery did you do anything to remove the static discharge like holding down the power button or removing the ram? Have you tested the ram one dimm at a time to see if theres a problem with the sticks of ram or dimm slots. Try the ram in one dimm slot then the other then try the other dimm in one slot then the other. let use know how it works out. Hope this helps